scholarly journals Atypical residency of short-beaked common dolphins ( Delphinus delphis ) to a shallow, urbanized embayment in south-eastern Australia

2016 ◽  
Vol 3 (9) ◽  
pp. 160478 ◽  
Author(s):  
Suzanne Mason ◽  
Chandra Salgado Kent ◽  
David Donnelly ◽  
Jeffrey Weir ◽  
Kerstin Bilgmann
Keyword(s):  
Common Dolphin ◽  
Small Community ◽  
Delphinus Delphis ◽  
Photo Identification ◽  
South Eastern ◽  
Eastern Australia ◽  
Face Threats ◽  
Common Dolphins ◽  
South Eastern Australia

Short-beaked common dolphins ( Delphinus delphis ) are typically considered highly mobile, offshore delphinids. This study assessed the residency of a small community of short-beaked common dolphins in the shallow, urbanized Port Phillip Bay, south-eastern Australia. The ability to identify common dolphins by their dorsal fin markings and coloration using photo-identification was also investigated. Systematic and non-systematic boat surveys were undertaken between 2007 and 2014. Results showed that 13 adult common dolphins and their offspring inhabit Port Phillip Bay, of which 10 adults exhibit residency to the bay. The majority of these adults are reproductively active females, suggesting that female philopatry may occur in the community. Systematic surveys conducted between 2012 and 2014 revealed that the dolphins were found in a median water depth of 16 m and median distance of 2.2 km from the coast. The shallow, urbanized habitat of this resident common dolphin community is atypical for this species. As a result, these common dolphins face threats usually associated with inshore bottlenose dolphin communities. We suggest that the Port Phillip Bay common dolphin community is considered and managed separate to those outside the embayment and offshore to ensure the community's long-term viability and residency in the bay.

Crop responses to lime in long-term pasture-crop rotations in a high rainfall area in south-eastern Australia

2001 ◽  
Vol 52 (3) ◽  
pp. 329 ◽  
Author(s):  
G. D. Li ◽  
K. R. Helyar ◽  
M. K. Conyers ◽  
B. R. Cullis ◽  
P. D. Cregan ◽  
...  
Keyword(s):  
Crop Production ◽  
Acid Soils ◽  
Crop Rotations ◽  
Severe Drought ◽  
High Rainfall ◽  
South Eastern ◽  
Permanent Pasture ◽  
Eastern Australia ◽  
South Eastern Australia

A long-term trial, known as ‘managing acid soils through efficient rotations’ (MASTER), commenced in 1992 to develop and demonstrate a cropping system that is economically viable on the highly acid soils of the traditional permanent pasture region in south-eastern Australia, so that their fertility is sustained or improved. There were 2 permanent pasture systems and 2 pasture–crop rotations, each with and without lime. This paper reports the effect of lime on crop production over the first cycle (6 years). On annual pasture–crop rotations, lime significantly increased the dry matter production at anthesis and grain yields of wheat (cv. Dollarbird) compared with the unlimed treatments. Averaged across years from 1992 to 1997 (excluding the severe drought year 1994), wheat crops produced 1.6 t/ha more grain on the limed treatments than on the unlimed treatments (3.6 v. 2.0 t/ha). On perennial pasture–crop rotations, the lime effects varied with crops grown at each phase and year. For example, despite being tolerant of acidity, oats (cv. Yarran) responded to lime in 1996. Likewise, triticale (cv. Abacus) responded to lime in 1997. Wheat (cv. Dollarbird) that is moderately tolerant to acidity responded to lime in phase 6 from 1992 to 1997 excluding 1994 (3.5 v. 1.7 t/ha). Acid-tolerant wheat varieties, triticale, and narrow-leaf lupins are considered the most viable crops for the soil and climatic conditions encountered in this high rainfall (5000—800 mm per annum) area of south-eastern Australia.

Pasture and sheep responses to lime application in a grazing experiment in a high-rainfall area, south-eastern Australia. II. Liveweight gain and wool production

2006 ◽  
Vol 57 (10) ◽  
pp. 1057 ◽  
Author(s):  
G. D. Li ◽  
K. R. Helyar ◽  
M. K. Conyers ◽  
L. J. C. Castleman ◽  
R. P. Fisher ◽  
...  
Keyword(s):  
Rotation Period ◽  
Acid Soils ◽  
Pasture Production ◽  
Wool Production ◽  
South Eastern ◽  
Eastern Australia ◽  
Lime Application ◽  
High Rainfall Area ◽  
South Eastern Australia

‘Managing Acid Soils Through Efficient Rotations (MASTER)’ is a long-term pasture–crop rotation experiment commenced in 1992. One of the objectives was to demonstrate the extent of crop, pasture, and animal responses to lime application on a typical acidic soil in the 500–800 mm rainfall zone of south-eastern Australia. Two types of pastures (perennial v. annual pastures) with or without lime application were established in 1992. Fifteen- to eighteen-month-old Merino hoggets were used as test animals and were changed annually. This paper reports the results of sheep responses to liming from the 4 continuous pasture treatments over 6 years from 1992 to 1997. The stocking rate was the same on all plots within a treatment during each rotation period, but was varied between treatments based on the pasture availability and sheep body condition. The most important findings from this study are that the limed treatments carried 29% and 27% more stock (up to 4 DSE/ha) than the unlimed treatments for perennial and annual pastures, respectively. As a result, the limed perennial pastures produced 27% more liveweight gain (62 kg/ha.year) and 28% more greasy wool (13 kg/ha.year) than unlimed perennial pastures, whereas the limed annual pastures produced 34% more liveweight gain (77 kg/ha.year) and 24% more greasy wool (11 kg/ha.year) than unlimed annual pastures. The significant responses to lime in liveweight and wool production were detected from the second growing season after the pastures were established. The increased sheep productivity on the limed treatment was due to a combination of increased pasture production and improved pasture quality. Perennial pastures showed a slight advantage in wool production, but not in liveweight gain. However, the seasonal variation of liveweight was greater on annual pastures than on perennial pastures. The larger variation in liveweight change could lead to more adverse effects on wool quality especially at high grazing pressures. Grazing management can be used to manipulate pasture and animal productivity to increase profits from lime use.

Utilization of Appetite for Sodium Salts to Control Rabbit Populations by Poisoning.

1975 ◽  
Vol 2 (2) ◽  
pp. 135 ◽  
Author(s):  
K Myers
Keyword(s):  
Sodium Chloride ◽  
Early Summer ◽  
Effective Control ◽  
Sodium Salts ◽  
Control Rabbit ◽  
South Eastern ◽  
Eastern Australia ◽  
Bait Stations ◽  
South Eastern Australia

Rabbits in subalpine areas in south-eastern Australia show a marked avidity for sodium salts during the spring and early summer months. During that period rabbit populations may be controlled by allowing access to soft wooden meranti pegs impregnated with sodium chloride and sodium luoroacetate (poison 1080). If the pegs are left out as permanent bait stations they produce long-term effective control. The method should be applicable to other areas in Australia where soil sodium is very low.

scholarly journals Short-term effects of tourism on the behaviour of common dolphins (Delphinus delphis) in the Azores

2017 ◽  
Vol 98 (5) ◽  
pp. 1187-1196 ◽  
Author(s):  
Arianna Cecchetti ◽  
Karen A. Stockin ◽  
Jonathan Gordon ◽  
José M.N. Azevedo
Keyword(s):  
Transition Probabilities ◽  
High Energy ◽  
Tourism Industry ◽  
Common Dolphin ◽  
Short Term ◽  
Delphinus Delphis ◽  
Critical Activity ◽  
Time Required ◽  
Common Dolphins

Short-term measures of behavioural responses of cetaceans to tourism operations have been used in many studies to interpret and understand potential long-term impacts of biological importance. The short-beaked common dolphin (Delphinus delphis) is the species most frequently observed in the Azores and constitutes an important component of the marine mammal tourism industry in this region. This study investigated the potential effects of tour boats on the behaviour of common dolphins off São Miguel, Azores, with particular focus on the changes in activity budget and the time required to resume activities after a tour boat interaction. Behavioural data were collected from land using a group focal-follow methodology. Markov chains were applied to analyse control and interaction sequences and to assess behavioural transition probabilities in both scenarios. In the presence of tour boats, dolphins significantly reduced the time spent foraging and increased the time engaged in other high energy activities. Dolphins also took significantly longer to resume feeding after an interaction occurred. The average bout length varied significantly between control and interaction scenarios, with foraging bouts being shorter during tour boats interactions. The results presented have management implications since feeding is a biologically critical activity. Disruption of foraging behaviour could lead to a decrease in energy intake for this population. With cetacean tourism likely to increase in the future, a precautionary approach to issuing new licences is advisable and any expansion would warrant an appropriate monitoring programme.

The population ecology of the squirrel glider (Petaurus norfolcensis) within a network of remnant linear habitats

2002 ◽  
Vol 29 (4) ◽  
pp. 329 ◽  
Author(s):  
Rodney van der Ree
Keyword(s):  
Agricultural Landscape ◽  
South Eastern ◽  
Linear Habitats ◽  
Continuous Forest ◽  
Eastern Australia ◽  
Squirrel Glider ◽  
Density Population ◽  
Natality Rate ◽  
South Eastern Australia

The geographic range of the squirrel glider (Petaurus norfolcensis) in south-eastern Australia largely corresponds with fertile soils highly suited for agriculture. As a consequence of extensive clearing for agriculture, the conservation of P. norfolcensis in south-eastern Australia is now reliant on a mosaic of many fragmented and isolated patches of woodland and forest. In this study, I investigated the population dynamics of P. norfolcensis in an agricultural landscape where most remnant woodland occurs as linear strips along roadsides, unused road reserves and watercourses. A total of 251 gliders were trapped 1343 times within the linear habitats between December 1996 and November 1998. Gliders were resident within the linear strips at 0.95–1.54 individuals ha–1, a density equal to, or greater than, that recorded elsewhere for the species in continuous forest. All adult females were reproductively active and the mean natality rate was 1.9 young per adult female per year. Overall, the population age-structure appeared to be stable. While currently supporting a stable, high-density population, the long-term viability of these remnants as habitat is not assured because roadside reserves are narrow, easily fragmented and subjected to a host of deleterious processes causing ongoing habitat loss and degradation.

The rise and fall of a translocated population of the endangered Macquarie perch, Macquaria australasica, in south-eastern Australia

2013 ◽  
Vol 64 (9) ◽  
pp. 838 ◽  
Author(s):  
Mark Lintermans
Keyword(s):  
Single Individual ◽  
Spawning Habitat ◽  
Management Activity ◽  
South Eastern ◽  
Millennium Drought ◽  
Eastern Australia ◽  
Term Monitoring ◽  
South Eastern Australia

Translocation is an increasingly popular conservation management activity worldwide, but the success of translocation is often not measured or reported. A population of the endangered Macquarie perch was imperilled by the damming in 1977 of the Queanbeyan River, near Canberra in south-eastern Australia. In November 1980, 66 adult Macquarie perch (309–389-mm total length) individuals were collected from the newlyformed reservoir, and translocated approximately 4 km upstream into the Queanbeyan River past a waterfall (which prevented access to spawning habitat). Five years of post-translocation monitoring at the release sites resulted in the capture of only a single individual in late 1981. Consequently, monitoring ceased because the translocation was assumed to have failed. However, subsequent angler reports and a preliminary survey in 1991 confirmed that some translocated fish had survived, and a small recruiting population had established. More intensive follow-up surveys and subsequent monitoring from 1996 to 2006 demonstrated an established population with consistent recruitment until 2001. However, after 2001, there was no evidence of recruitment and the population is now undetectable, with the prolonged ‘millennium drought’ (1997–2010) being the most plausible cause. The present study demonstrates the potentially ephemeral nature of assessments of success and failure, and the importance of targeted long-term monitoring programs.

Economic impact of Vulpia in temperate pasture systems in south-eastern Australia

2002 ◽  
Vol 42 (4) ◽  
pp. 465 ◽  
Author(s):  
D. T. Vere ◽  
P. M. Dowling ◽  
R. E. Jones ◽  
D. R. Kemp
Keyword(s):  
Management Strategies ◽  
Significant Proportion ◽  
Economic Benefits ◽  
Economic Effects ◽  
Economic Modelling ◽  
Benefit Cost Analysis ◽  
South Eastern ◽  
Eastern Australia ◽  
South Eastern Australia

An increasing incidence of annual grasses is considered to be a primary cause of decline in the productivity of Australia's temperate pasture systems. In particular, Vulpia (silver grass) comprises a significant proportion of the biomass of many temperate pastures and can seriously affect livestock productivity. The main economic effects of Vulpia include reducing pasture carrying capacities, contaminating produce and competing with more desirable pasture species. This paper presents the results of an economic evaluation of the costs of Vulpia and the long-term benefits of improving Vulpia management in the high-rainfall areas of south-eastern Australia. The evaluation used an integrated economic modelling system that determined the grazing system and livestock industry impacts of Vulpia and translated these into measures of economic welfare change that enabled the benefit-cost analysis of various levels of Vulpia management to be undertaken. With a focus on wool, the analysis established the high annual costs of Vulpia to wool producers and consumers, together with substantial long-term economic benefits that could potentially result from reducing the incidence of Vulpia in pastures. Total annual costs to the wool industry in the temperate pasture zone of New South Wales and Victoria ranged between A$7 and $30 million, while the potential discounted net benefits to the Australian and international wool industries were between $32 and $287�million over a 15-year period at a real discount rate of 5%. These estimates provide a strong economic basis for promoting improved management strategies for reducing Vulpia incidence in pastures.

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